On 06/28/2011 11:56 AM, Alan Conway wrote:
What happens if the consumer dies or cancel's mid-group in this case? Do we - replay the group from the beginning to another consumer? - drop the rest of the group? - continue sending to a new consumer from where the first consumer left off? - In which case do we provide a flag to let the new consumer know it's starting mid-group?
I would say it is business as usual. Any unacknowledged messages are redelivered to another available consumer. However the relative ordering between the messages in a group should not be lost.
In case (3) the assumption is that the application will only acknowledge after receiving the final message in the group, so the group will be acknowledged as a group.
At present the c++ broker does not support consumer identity that persists across loss of session. That I think is orthogonal to this however. (If it did then under requirement 2 you would maintain the association of group to consumer identity and not redeliver those messages until the consumer re-subscribed).
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